Optical communications device having a mounting core and method

Abstract

A parallel optical communications device is provided that has a mounting core that functions as a mounting system for mounting core components of the parallel optical communications device. In addition, the mounting core functions as a heat dissipation system for the core components of the parallel optical communications device, and also protects the core components and other elements of the communications device from dust and damage that can be caused by handling and other factors. In addition to performing the aforementioned functions, the mounting core is configured to enable the parallel optical communications device to be made extremely small in size while also protecting signal integrity.

1. A parallel optical communications device comprising:
 a circuit board, the circuit board having an upper surface and a lower surface and one or more electrical conductors therein, the circuit board having at least one integrated circuit (IC) mounted on the upper surface of the circuit board at a first mounting location of the circuit board; 
 a mounting core comprising a substantially rigid thermally conductive material to enable the mounting core to function as both a heat dissipation structure and as a mounting structure, the mounting core having an upper surface and a lower surface, the lower surface of the mounting core being attached at one or more locations thereof to one or more locations on the upper surface of the circuit board, the lower surface of the mounting core having a cutaway area formed therein where a portion of the mounting core beneath the upper surface of the mounting core is absent so that the at least one IC mounted on the upper surface of the circuit board is disposed within the cutaway area beneath the upper surface of the mounting core; 
 at least a first core IC mounted on the upper surface of the mounting core at a first mounting location of the mounting core; 
 a plurality of active optical devices mounted on the upper surface of the mounting core at a second mounting location of the mounting core, the core IC mounted on the upper surface of the mounting core being electrically connected to at least a plurality of the active optical devices to allow the core IC to control operations of the active optical devices to which the core IC is connected, and wherein at least some heat generated by one or both of the core IC and the active optical devices passes into the mounting core, and wherein at least some of the heat that passes into the mounting core is dissipated by the mounting core; and 
 an optics subsystem comprising a plurality of optical elements for directing light between respective ones of the active optical devices and respective ends of respective optical waveguides. 
 
     
     
       2. The parallel optical communications device of  claim 1 , wherein core IC is a laser diode driver IC, and wherein the active optical devices are laser diodes, the parallel optical communications device being a parallel optical transmitter. 
     
     
       3. The parallel optical communications device of  claim 1 , wherein core IC is a receiver IC, and wherein the active optical devices are photodiodes, the parallel optical communications device being a parallel optical receiver. 
     
     
       4. The parallel optical communications device of  claim 1 , further comprising:
 at least a second core IC mounted on the upper surface of the mounting core at a third mounting location of the mounting core, and wherein the first core IC is a laser diode driver IC and the second core IC is a receiver IC, and wherein a first subset of the active optical devices are laser diodes and a second subset of the active optical devices are photodiodes, the parallel optical communications device being a parallel optical transceiver. 
 
     
     
       5. The parallel optical communications device of  claim 1 , further comprising:
 at least a second core IC mounted on the upper surface of the mounting core at a third mounting location of the mounting core, and wherein the second mounting location of the mounting core where the plurality of active optical devices are mounted is in between and equidistant from the first and third mounting locations of the mounting core, and wherein the first and second core ICs are first and second laser diode driver ICs, respectively, and wherein a first subset of the active optical devices are laser diodes that are controlled by the first core IC and a second subset of the active optical devices are laser diodes that are controlled by the second core IC. 
 
     
     
       6. The parallel optical communications device of  claim 1 , wherein the mounting core has a first core portion and a second core portion, the first core portion having a side corresponding to the upper surface of the mounting core, the second core portion having a side corresponding to the lower surface of the mounting core, and wherein the first core portion has a width corresponding to a width of the upper surface of the mounting core in an X dimension of a Cartesian coordinate reference frame, and wherein the second core portion has a width corresponding to a width of the lower surface of the mounting core in the X dimension of the Cartesian coordinate reference frame, and wherein the width of the first core portion is greater than the width of the second core portion. 
     
     
       7. The parallel optical communications device of  claim 6 , wherein the cutaway area is formed in the second core portion, and wherein the cutaway area surrounds at least the IC mounted on the upper surface of the circuit board at the first mounting location of the circuit board and protects the IC mounted on the upper surface of the circuit board from external forces. 
     
     
       8. The parallel optical communications device of  claim 6 , wherein the electrical conductors of the circuit board include electrical conductors that carry high speed signals and electrical conductors that carry lower speed signals, and wherein the high speed electrical conductors are laid out in the circuit board such that the high speed electrical conductors either do not pass under the second core portion at all or only pass under the second core portion in one or more layers of the circuit board that are not adjacent the upper surface of the circuit board. 
     
     
       9. The parallel optical communications device of  claim 1 , further comprising:
 at least a second core IC mounted on the upper surface of the mounting core at a third mounting location of the mounting core, and wherein the second mounting location of the mounting core where the plurality of active optical devices are mounted is in between and equidistant from the first and third mounting locations of the mounting core; and 
 a bond wire protector comprising a first bond wire protector device and a second bond wire protector device, the first and second bond wire protectors device being mechanically coupled to first and second sides, respectively, of the mounting core, the first bond wire protector device protecting bond wires extending between the first core IC and the circuit board from forces that are exerted on the parallel optical communications device, the second bond wire protector device protecting bond wires extending between the second core IC and the circuit board from forces that are exerted on the parallel optical communications device. 
 
     
     
       10. The parallel optical communications device of  claim 9 , wherein the mounting core and the bond wire protector have keying features thereon that mate to mechanically couple the bond wire protector to the mounting core. 
     
     
       11. A method for mounting components in a parallel optical communications device, the method comprising:
 providing a circuit board, the circuit board having an upper surface and a lower surface and one or more electrical conductors therein, the circuit board having at least one integrated circuit (IC) mounted on the upper surface of the circuit board at a first mounting location of the circuit board; 
 providing a mounting core comprising a substantially rigid thermally conductive material to enable the mounting core to function as both a heat dissipation structure and as a mounting structure, the mounting core having an upper surface and a lower surface, the lower surface of the mounting core being attached at one or more locations thereof to one or more locations on the upper surface of the circuit board, the lower surface of the mounting core having a cutaway area formed therein where a portion of the mounting core beneath the upper surface of the mounting core is absent so that the at least one IC mounted on the upper surface of the circuit board is disposed within the cutaway area beneath the upper surface of the mounting core; 
 mounting at least a first core IC on the upper surface of the mounting core at a first mounting location of the mounting core; 
 mounting a plurality of active optical devices mounted on the upper surface of the mounting core at a second mounting location of the mounting core, the core IC mounted on the upper surface of the mounting core being electrically connected to at least a plurality of the active optical devices to allow the core IC to control operations of the active optical devices to which the core IC is connected, and wherein at least some heat generated by one or both of the core IC and the active optical devices passes into the mounting core, and wherein at least some of the heat that passes into the mounting core is dissipated by the mounting core; and 
 mechanically coupling an optics subsystem to one or more components of the optical communications device, the optics subsystem comprising a plurality of optical elements for directing light between respective ones of the active optical devices and respective ends of respective optical waveguides. 
 
     
     
       12. The method of  claim 11 , wherein core IC is a laser diode driver IC, and wherein the active optical devices are laser diodes, the parallel optical communications device being a parallel optical transmitter. 
     
     
       13. The method of  claim 11 , wherein core IC is a receiver IC, and wherein the active optical devices are photodiodes, the parallel optical communications device being a parallel optical receiver. 
     
     
       14. The method of  claim 11 , further comprising:
 mounting at least a second core IC on the upper surface of the mounting core at a third mounting location of the mounting core, and wherein the first core IC is a laser diode driver IC and the second core IC is a receiver IC, and wherein a first subset of the active optical devices are laser diodes and a second subset of the active optical devices are photodiodes, the parallel optical communications device being a parallel optical transceiver. 
 
     
     
       15. The method of  claim 11 , further comprising:
 mounting at least a second core IC on the upper surface of the mounting core at a third mounting location of the mounting core, and wherein the second mounting location of the mounting core where the plurality of active optical devices are mounted is in between and equidistant from the first and third mounting locations of the mounting core, and wherein the first and second core ICs are first and second laser diode driver ICs, respectively, and wherein a first subset of the active optical devices are laser diodes that are controlled by the first core IC and a second subset of the active optical devices are laser diodes that are controlled by the second core IC. 
 
     
     
       16. The method of  claim 11 , wherein the mounting core has a first core portion and a second core portion, the first core portion having a side corresponding to the upper surface of the mounting core, the second core portion having a side corresponding to the lower surface of the mounting core, and wherein the first core portion has a width corresponding to a width of the upper surface of the mounting core in an X dimension of a Cartesian coordinate reference frame, and wherein the second core portion has a width corresponding to a width of the lower surface of the mounting core in the X dimension of the Cartesian coordinate reference frame, and wherein the width of the first core portion is greater than the width of the second core portion. 
     
     
       17. The method of  claim 16 , wherein the cutaway area is formed in the second core portion, and wherein the cutaway area surrounds at least the IC mounted on the upper surface of the circuit board at the first mounting location of the circuit board and protects the IC mounted on the upper surface of the circuit board from external forces. 
     
     
       18. The method of  claim 16 , wherein the electrical conductors of the circuit board include electrical conductors that carry high speed signals and electrical conductors that carry lower speed signals, and wherein the high speed electrical conductors are laid out in the circuit board such that the high speed electrical conductors either do not pass under the second core portion at all or only pass under the second core portion in one or more layers of the circuit board that are not adjacent the upper surface of the circuit board. 
     
     
       19. The method of  claim 11 , further comprising:
 mounting at least a second core IC mounted on the upper surface of the mounting core at a third mounting location of the mounting core, and wherein the second mounting location of the mounting core where the plurality of active optical devices are mounted is in between and equidistant from the first and third mounting locations of the mounting core; and 
 mechanically coupling a bond wire protector comprising a first bond wire protector device and a second bond wire protector device to first and second sides, respectively, of the mounting core, the first bond wire protector device protecting bond wires extending between the first core IC and the circuit board from forces that are exerted on the parallel optical communications device, the second bond wire protector device protecting bond wires extending between the second core IC and the circuit board from forces that are exerted on the parallel optical communications device. 
 
     
     
       20. The method of  claim 19 , wherein the mounting core and the bond wire protector have keying features thereon that mate to mechanically couple the bond wire protector to the mounting core.